The study, published Monday in the journal Archives of Surgery, found that, “For all 10 procedures, white patients were more frequently treated by both high-volume hospitals and surgeons than were black, Asian and Hispanic patients.

”Averaging all procedures together, white patients benefited from both high-volume hospitals and high-volume surgeons in 37.6% of cases, compared to 20.6% of cases for black patients, 24.4% of cases for Asian patients, and 25.5% of cases for Latino patients, according to the study.

When the researchers took demographic and health variables into account, they found that blacks were less likely than whites to be treated by high-volume surgeons in high-volume hospitals in nine out of the 10 categories. The corresponding figure for Asians was five out of 10 categories, and for Latinos it was four out of 10, the study found.

The results showed a “persistent pattern” of racial disparities that “play out differently for different minority groups,” the authors wrote. But the study “does not support the common suggestion that health care disparities are driven primarily by differences in socioeconomic status,” they added. For instance, Asians were most likely to be either uninsured or on Medicaid, although they came from neighborhoods with higher socioeconomic status than blacks or Latinos.

Also, for half of the procedures, some racial groups got the same treatment as whites while others did not. That suggests that different factors may be at work for each minority group and each kind of health problem, they wrote. But the researchers weren’t able to pinpoint what those causes were. They did have some ideas, though.

Although New York City is a melting pot, it also anchors one of the five most segregated metropolitan areas in the country, according to U.S. census data. On top of that, only 9.5% of surgeons and 22% of hospitals in the study were classified as “high-volume,” and those hospitals may be clustered in neighborhoods populated by whites, they wrote. (To test this theory, it would be useful to see whether white and minority patients treated in a given hospital were equally likely to be treated by a high-volume surgeon.)

Another theory is that white patients are more likely to be referred to high-volume hospitals and surgeons because they “have access to better-informed referral networks,” the researchers wrote. But New York state has tried to even the playing field by publishing “report cards” on hospitals and surgeons. Since the program began in 1991, more black patients have been going to higher-quality surgeons for coronary artery bypass grafts, though the levels are still lower than for whites.

-- Karen Kaplan

Photo: Patients of color are less likely than whites to be treated by experienced surgeons or to receive care in high-volume hospitals, according to a new study. Credit: Lawrence K. Ho / Los Angeles Times